156813121 has 4 divisors (see below), whose sum is σ = 162220500. Its totient is φ = 151405744.

The previous prime is 156813109. The next prime is 156813161. The reversal of 156813121 is 121318651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121318651 = 443 ⋅273857.

It can be written as a sum of positive squares in 2 ways, for example, as 125888400 + 30924721 = 11220^2 + 5561^2 .

It is a cyclic number.

It is not a de Polignac number, because 156813121 - 2⁵ = 156813089 is a prime.

It is a super-3 number, since 3×156813121³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 156813121.

It is not an unprimeable number, because it can be changed into a prime (156813161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2703646 + ... + 2703703.

It is an arithmetic number, because the mean of its divisors is an integer number (40555125).

Almost surely, 2^156813121 is an apocalyptic number.

It is an amenable number.

156813121 is a deficient number, since it is larger than the sum of its proper divisors (5407379).

156813121 is an equidigital number, since it uses as much as digits as its factorization.

156813121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5407378.

The product of its digits is 1440, while the sum is 28.

The square root of 156813121 is about 12522.5045817520. The cubic root of 156813121 is about 539.2549407064.

The spelling of 156813121 in words is "one hundred fifty-six million, eight hundred thirteen thousand, one hundred twenty-one".